Tens of thousands of cars and vans will face the daily charge, with the extended area measuring 18 times larger than the central zone.

Any diesel cars built before 2015 will have to pay up plus pre-2006 petrols.

The zone includes an area up to the North and South Circular roads and will kick in from October 25, 2021.

Mr Khan made the announcement as he launched a new study of more than 3,000 primary school children in polluted areas of London and Luton, Bedfordshire, to test if policies to improve air quality help their health.

"Air pollution is a national health crisis and I refuse to stand back as thousands of Londoners breathe in air so filthy that it shortens our life expectancy, harms our lungs and worsens chronic illness.

"I promised hard-hitting measures to tackle our shameful air pollution and today City Hall is confirming the next stage of our plans to expand the ultra-low emission zone up to the North and South Circular roads."

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